1. Field of the Invention
The present invention relates to an apparatus providing minute powder particles for recycling of spent nuclear fuel, more particularly, an apparatus capable of processing a large amount of spent nuclear fuel even though its size is small, readily discharging a powder by gravity since the apparatus is vertically configured and reducing time required for oxidation.
2. Description of Related Art
Nuclear fuel is a material capable of producing energy by entering a nuclear reactor and causing a chain reaction of nuclear fission. Spent nuclear fuel is the material left after the nuclear fission.
Two methods are generally used for a management of spent nuclear fuel. One is a method of putting spent nuclear fuel in a rock bed in the ground to a depth of more than 500 meters and thoroughly isolating the spent nuclear fuel from the human ecosystem. This is known as permanent disposal. The other is a method of separating recyclable materials from spent nuclear fuel (this is referred to as ‘reprocessing’), reusing the separated nuclear fuel materials, and permanently disposing of high-level radioactive waste.
According to a conventional method, spent nuclear fuel burnt in a nuclear power plant is stored in a water tank without being processed. However, the longer the period of nuclear power generation, the more an amount of spent nuclear fuel accumulates. Consequently, a huge storage space is needed. Also, the necessity and danger of disposing the accumulated nuclear wastes remains.
Accordingly, a stable management technology for recycling of nuclear fuel in a solid state is urgently desired and some process apparatuses have been developed. However an additional apparatus is required when powder is transferred to a subsequent process after a powdering is completed since apparatuses using conventional arts have a small capacity and positioned laterally or tilted. Also, when solid spent nuclear fuel is oxidized, it takes over thirteen hours, is not able to pass through a mesh, and remains on the mesh since oxidized powder of spent nuclear fuel has a property of sticking together when reacting to oxygen in the air.
Since a mixing vane used for mixing powder consists of different types of blades, when the solid spent nuclear fuel is injected, the rotating mixing vane collides with the solid spent nuclear fuel and is broken by its blade. Because of the broken vane, graphite in the spent nuclear fuel also breaks, so that a radioactive toxic gas leaks out, which brings about environmental pollution.